There have been plenty of complaints to go around with iOS 7, ranging from general shouts of "nothing should ever change!" to more reasonable concerns about battery life, bugs, and troubles navigating Apple's new coat of paint. Nielsen Norman Group wanted to go through iOS 7 with a fine-toothed comb in order to break down exactly what Apple got right in iOS 7, and what it got wrong...Source: http://www.phonearena.com/news/Nielsen-says-iOS-7-needs-to-work-on-user-experience_id48330
